A charging device including a charging roller and a cleaning member is generally known. The charging roller charges a photosensitive member. The charging roller is in contact with the photosensitive member. The charging roller may therefore be contaminated by either or both of a trace of toner left on the photosensitive member and paper dust. Accordingly, the charging roller is cleaned using the cleaning member.
For example, Patent Literature 1 discloses a charging device including a charging roller supported by a supporting member. The charging roller is pressed against a photosensitive member through a spring member biasing the supporting member. Accordingly, the charging roller passively rotates in accompaniment to rotation of the photosensitive member. In contrast, a cleaning member therein rotates through driving force of a drum gear. As a result, the charging roller is cleaned.